Photosynthesis Flashcards
Zone A is the higher part of the rain forest and Zone B is the lower part of the rain forest. The rate of photosynthesis increased for both zones from midnight to noon and decreased from noon to midnight. The rate of photosynthesis is mostly always higher in zone A than zone B.
(a) Describe how why and the rates of photosynthesis of both zones change from noon to midnight.
(b) Explain why the rate of photosynthesis is mostly always higher in zone A than zone B.
(a) To a certain point, as the amount of light increases, the rate of photosynthesis increases. At noon the amount of light is at its maximum, thus the rate of photosynthesis is at its maximum. As the day progresses through from noon to midnight, the amount of light decreases until it is at its minimum, thus the rate of photosynthesis is at its minimum.
(b) As Zone A is above Zone B, the plants in Zone A receive more sunlight to photosynthesize at a greater rate than the plants in Zone B.
1 similar well-watered plant was placed in Set-up A and Set-up B each, in the same spot. There was a glass jar covering both plants. Set-up A had a chemical that gives out carbon dioxide inside the glass jar. Which jar had the most oxygen inside after 2 days? Explain why.
Set-up A. Set-up A contains a chemical that gives out carbon dioxide, so Set-up A has more carbon dioxide than Set-up B. Hence the plant in Set-up A will photosynthesize at a greater rate than the plant in Set-up B to release more oxygen.
A hydrilla plant was placed in a glass jar filled with water in a dark room. A lamp was placed some distance away from the plant. An hour later the amount of oxygen produced by the plant was recorded and the lamp was moved further away from the plant. It was noticed that as the distance between the plant and the lamp increases, the amount of oxygen that was produced decreases.
(a) Explain why this happens.
(b) Is this a fair test. State 1 reason why or why not.
(a)** When the lamp is nearer to the hydrilla, the intensity of the light is stronger. Thus the hydrilla’s rate of photosynthesis is higher, producing more oxygen.
(b) Yes. Only one variable, which is the distance of the lamp from the beaker, is changed while the rest of the variables were kept constant**.
The only source of light is from the lamp as the experiment is conducted in a dark room
** is the best answer
A hydrilla was put in a beaker filled with water. A lamp was put beside the beaker. When the lamp was on, the hydrilla produced bubbles. When the lamp was off the hydrilla did not produce any bubbles. Explain why.
The hydrilla plant can not photosynthesize without light to produce oxygen bubbles.
A freshly plucked leaf was immersed in a beaker of hot water in the presence of light. Bubbles were observed to appear on the surface of the leaves
(a) Give a reason for this observation
(b) It is observed that more bubbles appeared on the underside of the leaf as compared to the upper side of the leaf. What could be a possible explanation for this
(a) The freshly plucked leaves was still carrying out photosynthesis/respiration, thus releasing oxygen/carbon dioxide which was observed in the form of bubbles.
(b) There are more stomata found on the underside of he leaf than on the upper side of the leaf.
Photosynthesis in the presence of light, Respiration if without light.
A plant was put in a cupboard for 2 days and leaf A was sealed in a conical flask containing a solution that removes carbon dioxide. The plant is then placed in the sun for 6 hours. Leaf A and leaf B were tested for starch using an iodine solution.
What are most likely the results of the test of Leaves A and B. Explain your answer.
The iodine solution on leaf A will remain brownish yellow but the iodine solution on leaf B will turn dark blue. Leaf A cannot photosynthesize to produce starch as there is no carbon dioxide in the conical flask but leaf B can take in the carbon dioxide from the surrounding air to photosynthesize to produce starch.
A leaf was de-starched for 2 days before the experiment. Some parts of the leaf was white in color and the rest was green. Part A of the leaf was covered in aluminium foil and Part B of the leaf was white. The leaf was then put in the sun for 3 hours then tested for starch using iodine solution.
State whether there was any color change in both parts, and explain why.
Part A:
No change. The aluminium foil blocked the light from reaching Part A of the leaf. Thus, Part A cannot photosynthesize to produce sugar that can be stored as starch.
Part B:
No change. Part B of the leaf is white as there is no chlorophyll which contains a green pigment. Thus Part B photosynthesize to produce sugar that can be stored as starch.
A leaf of a tomato plant was plucked off and put in water of different temperatures. It was observed that the greatest number of bubbles observed to be produced is between 20 to 30 degrees. In cold countries, the temperature inside a greenhouse during the day is between 20 to 30 degrees, which is much warmer than the temperature outside. The tomato plants inside were observed to produce sweeter fruits than those outside. Explain why.
The bubbles are oxygen released by the leaf during photosynthesis. The greatest volume of oxygen was produced between 20 to 30 degrees, hence the rate of phototsynthesis is greater. The plants in the greenhouse photosynthesized at a faster rate than those outside, thus more food is stored inside the fruits, making it sweeter
